ABSTRACT Support is requested for an interdisciplinary effort to understand the key molecular and developmental events that regulate blood and vascular cells in inflammation, hemostasis and thrombosis with a focus on adhesive signaling. The four Projects will: 1) Test the hypothesis that direct interactions between Rap1 and talin1 plays an important role in platelet, leukocyte, and endothelial cell functions in inflammation, hemostasis and thrombosis. 2) Use newly developed imaging modalities to enable quantitative dynamic footprinting of the surface of neutrophils in contact with substrate to assess adhesion receptor clustering and conformation in response to specific molecular adaptor-adhesion receptor interactions. A particular focus is the structure-function of kindlin-3, the gene mutated in human leukocyte adhesion deficiency Type 3, and its relationship to talin. 3) An Early Stage Investigator will test the hypothesis that genetic inactivation of Krit1 or Heg1 in adult mice will protect against experimental inflammation or thrombosis. In collaboration with a structural biologist, he will extend studies to test the feasibility of pharmacologically disrupting the HEG1-KRIT1 complex to mimic the effects of genetic inactivation of these genes. 4) To assess the role of SHARPIN and associated components of the LUBAC linear ubiquitination complex in the functions of platelets and endothelial cells in inflammation, hemostasis, and thrombosis. This project will test the hypothesis that this newly-identified regulator of platelet and endothelial cell functions contributes to inflammation, hemostasis, and thrombosis. A scientific core unit, led by a world leader in murine models of inflammation, hemostasis, and thrombosis, will provide the individual projects with in vivo models and expertise required to establish the patho- physiological relevance of these novel molecular mechanisms.